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Biomedical subjects

L Bjersing

Publications and source records attributed to L Bjersing.

At least 37 records · Page 2Linked to original sources
PubMed1983

Effects of PGF2 alpha and indomethacin on ovulation and steroid production in the isolated perfused rabbit ovary.

Both ovaries of 31 rabbits were perfused with a chemically defined medium in vitro in a recirculation system. In one series of experiments, hCG (100 IU) was injected iv 5-6 h prior to anaesthesia and surgery. Approximately 1 h later the perfusion was started. One ovary was perfused as control while the other ovary was perfused with 5 micrograms/ml indomethacin or with indomethacin and 1 micrograms/ml PGF2 alpha. In another series of experiments the rabbits received no pretreatment prior to operation. Instead, bovine LH was added to the perfusion medium of both control and experimental ovaries. The experimental side also received either indomethacin or indomethacin and PGF2 alpha. Finally, the effect of PGF2 alpha in the absence of LH was compared to the control ovary receiving only LH. After injection of hCG in vivo, ovulations occurred in 4 of 5 control ovaries. Indomethacin completely blocked ovulation in 4 of the 5 ovaries treated, while PGF2 alpha restored ovulations in all the experimental ovaries. In the group of experiments where LH was added in vitro, ovulations were induced in all ovaries treated with varying LH doses. Furthermore, indomethacin blocked ovulation in 5 out of 7 ovaries, and PGF2 alpha restored ovulation in all ovaries. Fifty per cent of the ovaries treated only with PGF2 alpha (in the absence of LH) also ovulated. The pattern of steroid release did not differ between control ovaries, indomethacin treated ovaries, and indomethacin + PGF2 alpha treated ovaries. Ovaries treated in perfusion with PGF2 alpha alone had very low steroid levels compared to the ovaries treated with LH.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1982

The study of ovulation in the isolated perfused rabbit ovary. 1. Methodology and pattern of steroidogenesis.

A previously described technique for perfusion of the isolated rabbit ovary in a recirculating system (Ahrén et al., 1975) was modified for studies of preovulatory follicular development and ovulation. Follicular ruptures were induced either by injection of human chorionic gonadotropin (hCG) to the animal 5-6 h prior to perfusion or by adding luteinizing hormone (LH) directly to the medium during perfusion. Ovulation occurred 9-14 h after hCG injection in vivo and 7-13 h after the addition of LH in vitro. Ovulations did not occur unless the ovaries were stimulated by gonadotropin in vivo or in vitro. The patterns of release of estradiol-17 beta and progesterone into the medium are consistent with the measurements reported by others on these steroids in ovarian venous blood in vivo. This experimental model is likely to be useful in further exploration of the physiology, biochemistry and anatomy of ovulation.

Animals↗
PubMed1982

The preovulatory decline in follicular oestradiol is not required for ovulation in the rabbit.

Using a method of in vitro perfusion of the rabbit ovary with a chemically defined medium in a recirculation system, normal appearing follicular ruptures occurred following exposure of the ovaries to hCG in vivo (100 IU) or following addition of LH (0.25 microgram/ml of NIH B9) to the perfusate. The addition of oestradiol-17 beta (10 micrograms/ml) to the perfusate did not inhibit these follicular ruptures, although the follicular fluid oestradiol contents were increased more than 100-fold as compared to the control side not receiving the addition of oestradiol. These data suggest that the physiological decline of follicular oestrogen, normally observed in vivo prior to ovulation in the rabbit, is not required as part of the mechanism of ovulation and that normal appearing ovulations can occur even though follicular oestrogen levels are kept artificially elevated.

Animals↗
PubMed1981

The isolated perfused rabbit ovary-a model for studies of ovarian function. Ultrastructure after perfusion with different media.

In the present investigation the ultrastructure of isolated rabbit ovaries, perfused with different media for various time periods, was studied. The steroid hormone production by the perfused ovary was also determined. Perfusion with Medium 199 results in prominent interstitial ovarian oedema which increases with perfusion time. Even after the addition of 6-10% Dextran T40, oedema appears in the interstitial tissue of the ovary. Perfusion solutions with osmotically active colloid particles of large molecular size (Dextran T70; average molecular weight 70,000 and bovine serum albumin), cause less distortion in the ovarian structure, and ultrastructurally the ovarian tissues appear essentially the same as in the control ovaries. The results indicate that the perfused rabbit ovary, under strictly controlled conditions, can be used as an experimental model for studies of various aspects of ovarian function, including follicular rupture.

Animals↗
PubMed1977

Ultrastructure of gonadoblastoma and disgerminoma (seminoma) in a patient with XY gonadal dysgenesis.

The gross and fine morphology of gonadoblastoma and disgerminoma in a young phenotypic female with male karyotype and gonadal dysgenesis is described. Both the rudimentary gonads contain gonadoblastomas on the left side in association with a disgerminoma. In the light microscope the gonadoblastomas show peculiar hyaline masses, surrounded by Sertoli-like cells. In some areas a direct continuation between hyaline masses and basement membranes of round nests or large anomalous seminiferous tubules is obvious. At the ultrastructural level the hyaline masses consist of densely packed, largely concentric membranes closely similar to basement membranes or basal laminae of seminiferous tubules. These observations and the finding of transitional zones with gonadoblastoma elements in enlarged tubular structures suggest that gonadoblastomas originate inside tubules of dysgenetic testes. The peculiar hyaline masses with their concentric membranes might reflect hyperplasia and death of the Sertoli cells, each new generation of cells producing a basement membrane outside the preceding one.

Adolescent↗
PubMed1977

Angiography of the testicular artery. II. Cryptorchism and testicular agenesis.

A selective angiography of the testicular artery was performed in 7 boys and 7 men without a palpable testicle in order to localize cryptorchid testes or to establish testicular agenesis. The examination could be carried out in all cases, and the angiographic diagnosis was confirmed at operation and at a subsequent microscopy in the 12 cases hitherto operated upon. The width of the artery and its branches are also presented.

Adolescent↗
PubMed1977

Dysgerminomas (seminomas) in genetic males with female phenotype. One case of gonadal dysgenesis and gonadoblastoma and one of testicular feminization.

Gonadal tumors in patients with somatosexual ambiguity are rare but of considerable clinical and pathological interest. Two patients with dysgerminomas and abnormal sexual differentiation were recently treated at the Department of Gynecologic Oncology. One (Case 1) was an 18-year old girl and the other (Case 2) an unmarried woman of 58 years. In spite of their female phenotype both showed a male genotype, 46, XY. In Case 1 the dysgerminoma (or rather seminoma) originated in a gonadoblastoma in one of two dysgenetic testes but in Case 2 in one of two "feminizing testes". The clinico-pathological features of both cases will be reported and commented and the relation between the germ cell tumors, gonadal dysgenesis and the Y-chromosome will be discussed.

Adolescent↗
PubMed1976

Further studies of the epithelium covering preovulatory rabbit follicles with special reference to lysosomal alterations.

The fine structure of the surface epithelium over preovulatory rabbit follicles was examined parallel with visualization of acid phosphatase at the electron microscopical level. Small enzyme positive vesicles were pinched off from the Golgi cisternae and similar vesicles fused and got incorporated into larger lysosomes of dense body type. Some lysosomes appeared in direct continuity with tubular enzyme positive structures. Other possible ways of increase of the lysosomal pool are indicated and discussed. As in previous studies a maximal accumulation of lysosomes was found in the apical epithelium at 8 h after an ovulatory dose of human chorionic gonadotrophin (HCG); thereafter a gradual loss of lysosomes ensued. Before the lysosomes disappeared from the surface epithelium they changed in character. They became more electron-lucent and revealed a fine-fibrillar matrix. Dense bodies deep in the cell interior appeared to communicate with each other and with the extracellular space below the surface epithelium. Openings were never seen towards the peritoneal cavity. tthe loss of lysosomal content from the apical surface epithelium before follicle rupture appeared in many respects similar to the histamine release process in mast cells. tthe findings support our working hypothesis that the surface epithelium over tgraafian follicles is an essential source of proteolytic enzymes and that these may be released extracellularly and actively contribute to the dissolution of the follicular apex before rupture.

Acid Phosphatase↗